docs: def cross_idl(lon1, lon2, *lons):
      """
      Return True if two longitude values define line crossing international date
      line.
  
      >>> cross_idl(-45, 45)
      False
      >>> cross_idl(-180, -179)
      False
      >>> cross_idl(180, 179)
      False
      >>> cross_idl(45, -45)
      False
      >>> cross_idl(0, 0)
      False
      >>> cross_idl(-170, 170)
      True
      >>> cross_idl(170, -170)
      True
      >>> cross_idl(-180, 180)
      True
      """
      lons = (lon1, lon2) + lons
      l1, l2 = min(lons), max(lons)
      # a line crosses the international date line if the end positions
      # have different sign and they are more than 180 degrees longitude apart
      return l1 * l2 < 0 and abs(l1 - l2) > 180